#include <iostream>
#include <vector>
#include <unordered_map>
#include <cstdint>
#include <unistd.h>
#include <memory>
#include <functional>

using TaskFunc = std::function<void()>;
using ReleaseFunc = std::function<void()>;
class TimerTask
{
private:
    uint64_t _id;         // 定时器任务对象id
    uint32_t _timeout;    // 定时任务的超时时间
    bool _canceled;       // false-表示没有被取消
    TaskFunc _task_cb;    // 定时器对象要执行的定时任务
    ReleaseFunc _release; // 用于删除TimerWheel中保存的定时器对象信息
public:
    TimerTask(uint64_t id, uint32_t delay, const TaskFunc &cb)
        : _id(id), _timeout(delay), _task_cb(cb), _canceled(false)
    {
    }

    ~TimerTask()
    {
        if(_canceled == false)_task_cb();
        _release();
    }

    void Cancel()
    {
        _canceled = true;
    }

    void SetRelease(const ReleaseFunc& cb)
    {
        _release = cb;
    }

    uint32_t DelayTime()
    {
        return _timeout;
    }
};

class TimerWheel
{
private:
    using WeakTask = std::weak_ptr<TimerTask>;
    using PtrTask = std::shared_ptr<TimerTask>;
    int _tick;     // 当前的秒针，走到哪里释放哪里
    int _capacity; // 表盘最大数量，其实就是最大延迟时间
    std::vector<std::vector<PtrTask>> _wheel;
    std::unordered_map<uint64_t, WeakTask> _timers; //使用任务ID找到对应的weak_ptr
private:
    void RemoveTimer(uint16_t id)
    {
        auto it = _timers.find(id);
        if(it != _timers.end())
        {
            _timers.erase(it);
        }
    }
public:
    TimerWheel()
        : _capacity(60),
          _tick(0),
          _wheel(_capacity)
    {
    }
    void TimerAdd(uint64_t id, uint32_t delay, const TaskFunc& cb) //添加定时任务
    {
        PtrTask pt(new TimerTask(id, delay, cb));
        pt->SetRelease(std::bind(&TimerWheel::RemoveTimer, this, id));
        int pos = (_tick + delay) % _capacity;
        _wheel[pos].push_back(pt);
        _timers[id] = WeakTask(pt);
    }
    void TimerRefresh(uint64_t id)//刷新/延迟定时任务
    {
        //通过保存的定时器对象的weakptr构造一个shared_ptr出来，添加到轮子中
        auto it = _timers.find(id);
        if(it == _timers.end())
        {
            //没有找到定时任务
            return;
        }
        PtrTask pt = it->second.lock();//lock获取weakptr管理的对象对应的shared_ptr;
        int delay = pt->DelayTime();
        int pos = (_tick + delay) % _capacity;
        _wheel[pos].push_back(pt);
    }
    void TimerCancel(uint64_t id)
    {
        auto it = _timers.find(id);
        if(it == _timers.end())
        {
            //没有找到定时任务
            return;
        }
        PtrTask pt = it->second.lock();
        if(pt) pt->Cancel();
    }
    //这个函数每秒被执行一次，相当于秒针向后走了一步
    void RunTimeTask()
    {
        _tick = (_tick + 1) % _capacity;
        _wheel[_tick].clear();
    }
};

class Test
{
public:
    Test()
    {
        std::cout << "构造" << std::endl;
    }
    ~Test()
    {
        std::cout << "析构" << std::endl;
    }
};

void DelTest(Test* t)
{
    delete t;
}

int main()
{
    TimerWheel tw;
    Test* t = new Test();
    tw.TimerAdd(888, 5, std::bind(DelTest, t));
    for(int i = 0; i < 5; i++)
    {
        sleep(1);
        tw.TimerRefresh(888);//刷新定时任务
        tw.RunTimeTask();//向后移动指针
        std::cout << "刷新了一下定时任务， 重新需要5s中后才会销毁\n";
    }
    tw.TimerCancel(888);
    while(1)
    {
        sleep(1);
        std::cout << "-------------------\n";
        tw.RunTimeTask();//向后移动指针
    }
    return 0;
}